1. Field of the Invention
The invention relates to techniques and systems for producing ultrasonic cross-sectional images of a body, wherein a number of consecutive and at least partly overlapping scans of the body are made by the pulse echo method in one scanning plane to produce digital image signals corresponding to the received echoes. Each scan comprises a predetermined number of scanning lines; each such line comprises a predetermined number of scanning dots and there is a predetermined time interval between corresponding dots of consecutive scans.
2. Description
It is known (IEEE Transactions on Sonics and Ultrasonics, Vol. SU-31, No. 4, July 1984, pp. 195-217) that noise which impairs image quality in such systems can be reduced by averaging the image signals over a sequence of images; unfortunately, movements in the zone under examination cause blurring of the resulting image. This is a considerable disadvantage, particularly in medical ultrasonic diagnosis.
It is therefore an object of the invention to obviate this disadvantage.